SMAD4 and multiple endocrine neoplasia type 1: Notably, one patient with an APC gene mutation also harbored a SMAD4 (SMAD family member 4) gene mutation, while another patient with a SMAD4 gene mutation (n = 2, 14.29%) concurrently presented with a MEN1 (Multiple Endocrine Neoplasia Type 1) mutation (n = 1, 7.14%).